High Potassium (Hyperkalemia)

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is high potassium (hyperkalemia)?

High potassium occurs when blood levels of potassium are higher than normal. Normal values can vary slightly between testing labs. Labs will provide a reference range along with the individual’s measured potassium level. This is the normal range of potassium values for that particular lab. In general, a normal potassium level is between 3.6 and 5.2 mEq/L (also expressed as mmol/L, or millimoles/L). The medical term for an abnormally high potassium level is hyperkalemia.

Potassium is an electrolyte and nutrient you take in through your diet. It’s important for normal functioning of nerve and muscle cells. Your heart is a muscle and needs potassium like other muscles in your body. When potassium is too high, it can cause problems for your heart. High potassium levels can also interfere with the heart’s electrical system. This can lead to heart arrhythmias, heart attack, and even death. Unfortunately, a serious health problem may be the first sign of high potassium.

The kidneys are responsible for clearing extra potassium from the blood. If the kidneys are diseased or don’t work the way they should, the extra potassium can build up in the blood. There are other possible causes of high potassium levels. This includes drug side effects, dehydration, and severe injuries or burns.

High potassium treatment depends on the severity of the elevation. Mildly elevated levels may only require a reduced-potassium diet. Medicines can help lower potassium levels in people who need more than just dietary changes. Very high potassium requires emergency medical treatment. 

Doctors usually find high potassium on a blood test. When signs and symptoms develop, it can be life threatening. Seek immediate medical care (call 911) if you develop sudden symptoms, such as heart palpitations, chest pain, passing out, or paralysis.

What are the symptoms of high potassium (hyperkalemia)?

People often have no symptoms of high potassium. If symptoms are present, they are often mild and nonspecific. Hyperkalemia symptoms also tend to develop slowly over weeks or months.

Common symptoms

Common symptoms of high potassium include: 

Serious symptoms that might indicate a life-threatening condition

In some cases, high potassium can be life threatening. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including:

Regular medical care can help find high potassium levels before they become serious. Doctors routinely check potassium levels when ordering lab tests. This includes a basic metabolic panel or chemistry panel-a collection of multiple vital blood chemistry measurements. If you take medicines that can affect potassium or have other risk factors, your doctor will monitor your levels more closely.

What causes high potassium (hyperkalemia)?

The most common cause of high potassium is kidney disease, either acute or chronic. Healthy kidneys remove excess potassium from the blood and excrete it in urine. Damaged or diseased kidneys can’t perform this function effectively. As a result, potassium builds up in the blood, causing hyperkalemia. Another common cause of high potassium is taking medicines that interfere with this process. Examples include ACE (angiotensin-converting enzyme) inhibitors and potassium-sparing diuretics, such as triamterene.

Less common causes include a glandular condition called Addison’s disease, extensive burns, severe muscle damage, dehydration, and severe bleeding. Taking in too much potassium through supplements or salt substitutes can play a role in high potassium as well.

What are the risk factors for high potassium (hyperkalemia)?

A number of factors increase the risk of developing high potassium. You may be at risk if you have the following risk factors:

Reducing your risk of hyperkalemia

You may be able to lower your risk of high potassium by:

  • Avoiding salt substitutes and potassium supplements unless your doctor prescribes them

  • Effectively treating diabetes

  • Limiting or avoiding foods high in potassium if your doctor recommends it

If you are at risk of high potassium, your doctor will monitor your blood levels regularly. Catching any changes early can help your doctor make adjustments and avoid a problem.

How is high potassium (hyperkalemia) treated?

Treating high potassium depends on how high the level is and the cause. When medicines or supplements could be the cause, doctors may recommend changes to correct potassium levels.

Mild elevations may respond to dietary changes, such as avoiding high-potassium foods. This may include vegetables, such as asparagus, avocados, squash, pumpkin, potatoes, and tomatoes and tomato sauce. Fruits to avoid may include bananas, melons, dried fruit, kiwifruit, nectarines, oranges and their juice.

Higher levels may require medicines to restore potassium balance. Doctors can use diuretics that help the kidneys excrete potassium. They can also use potassium binders. These drugs keep the body from absorbing potassium from food, which prevents it from entering the bloodstream. 

Very high potassium levels require emergency medical treatment. This can involve IV (intravenous) medicines to decrease potassium levels and counteract potassium’s effects on the muscles and heart. Dialysis may be necessary if kidney function is very poor or declining.

What are the potential complications of high potassium (hyperkalemia)?

For many people, high potassium is mild and doctors can identify the underlying cause. In these cases, it usually resolves once doctors address the problem.

When the cause is ongoing, the problem will likely recur. Severe cases of high potassium can lead to serious complications. This includes heart arrhythmias, heart attack, and cardiac arrest. Any of these are potentially fatal.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2022 Jan 1
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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